Update swagger-documentation.md

Author: markamos

articles/cognitive-services/Speech-Service/swagger-documentation.md

@@ -14,7 +14,7 @@ ms.author: erhopf
 
 # Swagger documentation
 
-The Speech service offer a Swagger specification to interact with a handful of REST APIs used to import data, create models, test model accuracy, create custom endpoints, queue up batch transcriptions, and manage subscriptions. Most operations available through the Custom Speech portal can be completed programmatically using these APIs.
+The Speech service offers a Swagger specification to interact with a handful of REST APIs used to import data, create models, test model accuracy, create custom endpoints, queue up batch transcriptions, and manage subscriptions. Most operations available through the Custom Speech portal can be completed programmatically using these APIs.
 
 > [!NOTE]
 > Both Speech-to-Text and Text-to-Speech operations are supported available as REST APIs, which are in turn documented in the Swagger specification.